JPH04251244A - Production of photosensitive silver halide - Google Patents

Abstract

PURPOSE:To produce photosensitive silver halide having improved reciprocity law failure especially at high illuminance in an org. solvent and to make the silver halide fit for a thermally developable photo-sensitive material in which an image can be written with laser light at a high speed. CONSTITUTION:When an Ag ion feeding body is allowed to react with a halogen ion feeding body in an org. solvent to produce photosensitive silver halide, an Ir ion feeding body is added.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing photosensitive silver halide for use in dry heat-developable photosensitive materials, and more particularly to a method for producing photosensitive silver halide with improved high illuminance failure.

0002

[Prior Art] Silver halide photographic light-sensitive materials that undergo wet development are superior to other light-sensitive materials, such as diazo photography and electrophotography, in terms of photosensitivity, gradation, image quality, etc. , has been widely used. However, wet development processing requires precise control of the preparation of processing solutions and processing temperature and time. Furthermore, in recent years, the tendency for gas and solid-state laser light sources to become commonplace has required further simplification and shortening of processing time. Heat-developable photosensitive materials are known that can be rapidly processed by heat development in order to avoid wet development. This heat-developable photosensitive material can be used, for example, in ``Fundamentals of Photographic Engineering,'' Non-Silver Salt Photography Edition (
Coronasha Publishing, 1982), pages 242-255,
It is described in Japanese Patent Publication No. 43-4921, No. 43-4924, etc., and is composed of a photosensitive silver halide, a reducing agent, an organic silver salt oxidizing agent, and a hydrophobic binder, and these compositions are dissolved in an organic solvent. Alternatively, it can be produced by dispersing it, coating it on a support and drying it. However, this technology for heat-developable photosensitive materials could not be used for image writing by high-intensity, short-time exposure using a laser because it caused high-intensity failure. The reason for this is that the method for producing photosensitive silver halide, which is the photosensitive component of this heat-developable photosensitive material, in an organic solvent is essentially different from that of wet silver halide photosensitive materials, and the conventional reciprocity law failure occurs. technology, such as the special public
This is because the techniques for doping heavy metals such as rhodium, iridium, and thallium described in Japanese Patent Publication No. 4935 and Japanese Patent Publication No. 49-33781 cannot be applied as they are.

0003

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to establish a technique for producing photosensitive silver halide in an organic solvent with improved reciprocity failure, particularly high-intensity failure, and to produce a photosensitive silver halide in an organic solvent. High-speed image writing (1×1
It is an object of the present invention to provide a method for producing photosensitive silver halide suitable for a heat-developable photosensitive material capable of developing a photosensitive material of 0-5 sec to 1 x 10-7 sec/dot).

0004

[Means for Solving the Problems] The object of the present invention is to produce a photosensitive silver halide by reacting a silver ion donor (a) and a halide ion donor (b) in an organic solvent (c). This could be achieved by adding an iridium ion donor (d). Further, the iridium ion donor (d) is added in an amount of 5 x 10-5 to 5 x 10-3 mol per 1 mol of the silver ion donor (a), and the silver ion donor (a) and the halogen ion donor are added. More favorable results were obtained by adding the iridium ion donor (d) after at least 90% of the reaction step (b). At least 90 of the reaction steps
%, the photosensitive silver halide obtained by adding the iridium ion donor (d) contains iridium ions near the surface of the silver halide crystal. If the amount of iridium ion donor (d) added is less than 5 x 10-5 mol per 1 mol of the total silver ion donor (a) involved in the reaction, the effect will be low; If it exceeds this, the fog density will increase along with desensitization.

The photosensitive silver halide of the present invention includes silver chloride,
Silver bromide, silver chlorobromide, silver iodobromide, silver iodochloride, and silver iodochlorobromide are preferred, and photosensitive silver halides in which 90 mol % or more is silver bromide are particularly preferred.

[0006] Known methods can be applied to the method for producing the photosensitive silver halide of the present invention. This preparation method is described, for example, in US Pat. No. 3,713,833 and US Pat.
No. 7, Special Publication No. 58-21249, Special Publication No. 1987-1
No. 567, Special Publication No. 2-4889, Special Publication No. 2-6045
No., Special Publication No. 2-7446, Special Publication No. 2-7447, etc.
It is stated in each publication.

Silver ion donor (a) used in the present invention
Examples include inorganic silver compounds soluble in organic solvents, particularly polar organic solvents described below, and organic silver compounds soluble or dispersible in polar organic solvents. Specific examples of compounds include inorganic silver salts such as silver perchlorate and silver nitrate, silver complex salts such as silver ammonium complex salts and silver amine complex salts, silver acetate, silver trifluoroacetate, silver propionate, silver caprate, and lauric acid. Silver, silver myristate, silver palmitate, silver stearate, silver behenate, silver adipate, silver sebacate, silver benzotriazole, silver saccharin, silver phthalazinone, 3
-mercapto-4-phenyl-1,2,4-triazole silver, 4-hydroxy-6-methyl-1,3,3a,
These are organic silver salts such as silver 7-tetrazaindene and silver salt of 2-(S-ethylthioglycolamide)-benzothiazole.

Examples of the halogen ion donor (b) used in the present invention are inorganic halogen compounds or organic halogen compounds that are soluble in organic solvents, particularly polar organic solvents or polar organic solvents containing water. As a specific compound example, as an inorganic halogen compound, general formula MX
Mention may be made of compounds represented by n. However, in the formula, M is a hydrogen atom or a metal atom (for example, strontium, cadmium, zinc, sodium, barium, cesium, calcium, iron, nickel, magnesium, potassium, aluminum, antimony, gold, cobalt, mercury, lead, beryllium, lithium, indium, iridium, rhodium, palladium, platinum, bismuth, etc.), X represents a chlorine atom, a bromine atom, or an iodine atom, and n represents the valence of each cation. Examples of inorganic halogen compounds include halogen-containing metal complexes such as K2PtCl6,
K2PtBr6, HAuCl4, (NH4)3IrC
l6, (NH4)3RuCl6, K3PhCl6
etc. can be mentioned. Examples of organic halogen compounds include compounds represented by the following general formula (I) or (II).

[0009]

[Chemical formula 1]

In the formula, X represents a chlorine atom, a bromine atom, or an iodine atom, and Z represents a group of nonmetallic atoms necessary to form a 4- to 8-membered ring, and this 4- to 8-membered ring can be combined with other rings. May be condensed. Z is preferably a 5-membered ring or a 6-membered ring, and specific examples include a pyrrole ring, a pyrroline ring, a pyrrolidine ring, an imidazoline ring, an imidazolidine ring, a pyrazoline ring, an oxazolidine ring, a piperidine ring, an oxazine ring, a piperazine ring, and an indoline ring. Examples include rings. Furthermore, Z is a 4- to 8-membered lactam ring, a hydantoin ring,
A cyanuric ring, hexahydrotriazine ring, indoline ring, etc. may be formed. Furthermore, this ring includes an unsubstituted or substituted alkyl group, an unsubstituted or substituted aryl group,
It may have a substituent such as an alkoxy group, a halogen atom, or an oxo group. A represents a carbonyl group or a sulfonyl group, R1 and R2 are a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted aryl group,
Represents an alkoxy group.

Representative examples of compounds represented by the above general formula (I) include N-brom succinimide, N-bromotetrafluorosuccinimide, N-bromphthalimide, N-bromglutarimide, and 1,3-dibromide. -5,5-dimethyl-2,4-imidazolidinedione, N,N'-dibromo-5,5-diethylbarbituric acid, N-bromoisocyanuric acid, N,N'-
Dibromoisocyanuric acid, N-bromooxazolinone, N-bromophthalazinone, N-chlorsuccinimide, N-iodosuccinimide, N-chlorphthalimide, N-bromusaccharin, N-bromocaprolactam, N-bromobutylene Rolactam, N,N'-dibromthiohydantoin and the like can be mentioned.

Representative examples of compounds represented by the above general formula (II) include N-bromoacetamide, N-bromoacetanilide, N-bromobenzenesulfonylanilide, N-bromobenzamide, N-chloroacetamide, and N-bromonaphtho. amide, N-bromo-P-hydroxybenzamide, and the like.

Further, halogenated melamine can also be used as the organic halogen compound, and specific examples include tribromemelamine and trichloromelamine.

Furthermore, as the organic halogen compound, a C-halogeno compound represented by the following general formula (III) is also effective.

[0015]

[Case 2]

In the formula, X represents a chlorine atom, a bromine atom, or an iodine atom, and R3, R4, and R5 may be the same or different, and each represents a hydrogen atom, an unsubstituted or substituted alkyl group, or an unsubstituted or substituted aryl group. , a nitro group, an acyl group, an unsubstituted or substituted amide group, an unsubstituted or substituted aryl group, a sulfonyl group bonded to an alkyl group, or a halogen atom. However, at least one of R3, R4, and R5 helps release a halogen atom, and represents, for example, a nitro group, an unsubstituted or substituted aryl group, an alkenyl group, an acyl group, an amide group, a sulfonyl group, and the like.

Examples of the compound represented by the above general formula (III) include α-haloketone compounds, α-haloamide compounds, halosulfonyl compounds, halonitro lower alkane compounds, and compounds having an unsaturated bond at the carbon β position relative to the halogen atom. can be mentioned.

Specific examples of the compound represented by the general formula (III) include α-bromoacetophenone, α-chloroacetophenone, α-bromo-α-phenylacetophenone, α-bromo-1,3-diphenyl-1,3 −
Propanedione, α-bromo-2,5-dimethoxyacetophenone, α-bromomethylsulfonylbenzene,
α-bromo-α-benzenesulfonylacetamide, α
-Chlor-α-(p-tolylsulfonyl)acetamide, α-bromo-γ-nitro-β-phenylbutyrophenone, α-iodo-γ-nitro-β-phenylbutyrophenone, 2-bromo-2-nitro-1,3 -propanediol, 2-bromo-2-nitrotrimethylene-1,
3-bis(phenyl carbonate), α-bromotoluene, α,p-dibromotoluene, α,α'-dibromo-m-xylene, α,α,α',α'-tetrabromo-p-xylene, 3- Examples include bromopropene and the like. Among the above-mentioned compound examples, compounds in which the carbon at the β-position of the halogen atom has an unsaturated bond, such as α-bromotoluene and 3-bromopropene, are particularly useful.

Onium halide compounds are also useful as halogen ion donors in the present invention, and specific examples include ammonium bromide, trimethylphenylammonium chloride, cetylethyldimethylammonium bromide, trimethylbenzylammonium bromide, tetraethylphosphonium bromide, and trimethylsulfonium bromide. Examples include phonium chloride.

In the present invention, the silver ion donor as component (a) and the halogen ion donor as component (b) are mixed, and all or most of the silver ion donor as component (a) is photosensitively halogenated. Since the reaction for converting into silver is carried out in an organic solvent, the amount of the halogen ion donor (component (b)) used may be stoichiometric with respect to the silver ion donor (component (a)). However, it is preferable to use an excess amount of the halogen ion donor (component (b)), i.e., in the range of about 1.0 mol to about 3.0 mol per 1 mol of the silver ion donor (component (a)). .

[0021] In the present invention, the organic solvent (c) used in the reaction of component (a), the silver ion donor, and component (b), the halogen ion donor, is liquid at the reaction temperature, and the organic solvent (c) is liquid at the reaction temperature. There is no particular limitation as long as the ion donor can be uniformly dissolved or dispersed and a certain amount of the halogen ion donor (component (b)) can be dissolved. Specifically, alcohols, ketones, aliphatic hydrocarbons, aromatic hydrocarbons, esters, ethers, acid amides, and the like can be used alone or as a mixture.

Specific examples of alcohols include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, n-amyl alcohol, isoamyl alcohol, n-amyl alcohol, and n-butyl alcohol.
- Aliphatic saturated alcohols such as hexyl alcohol, aliphatic unsaturated alcohols such as allyl alcohol and propargyl alcohol, alicyclic alcohols such as cyclopentanol and cyclohexanol, aralkyl alcohols such as benzyl alcohol and cinnamyl alcohol, ethylene glycol, Examples include polyhydric alcohols such as glycerin.

Specific examples of ketones include acetone, methyl ethyl ketone, methyl propyl ketone, isopropyl methyl ketone, butyl methyl ketone, aliphatic saturated ketones such as isobutyl methyl ketone, methyl vinyl ketone,
Examples include unsaturated aliphatic ketones such as methylhepteneketone, alicyclic ketones such as cyclobutanone and cyclohexanone, and aromatic ketones such as acetophenone, propiophenone and butylphenone.

Specific examples of esters include methyl formate, propyl formate, amyl formate, ethyl acetate, methyl acetate, butyl acetate, isobutyl acetate, methyl propionate,
Examples include ethyl propionate, isopropyl propionate, methyl butyrate, ethyl butyrate, ethyl isobutyrate, methyl isovalerate, isopropyl isovalerate, methyl benzoate, and ethyl phthalate.

Specific examples of ethers include saturated aliphatic ethers such as diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, methyl butyl ether, ethylpropyl ether, and ethylisoamyl ether; Examples include saturated aliphatic ethers, aromatic ethers such as anisole and phenyl ether, and cyclic ethers such as tetrahydrofuran and dioxane.

Specific examples of aliphatic hydrocarbons include n
-Heptane, n-hexane, 3-methylpentane, 2
, 3-dimethylbutane, cyclohexane, cycloheptane, and unsaturated aliphatic hydrocarbons such as cyclohexene, cyclopentadiene, and cyclopentene.

Specific examples of aromatic hydrocarbons include benzene, toluene, xylene, chlorobenzene, indene, and tetralin. In addition, solvents containing nitrogen atoms or sulfur atoms, such as dimethylacetamide, dimethylformamide, and dimethyl sulfoxide, can also be used.

Particularly preferred among the above organic solvents are polar alcohols or ketones alone or in mixtures with the other solvents mentioned above. Mixed systems of water-alcohols and water-ketones can also be used.

Among the above reaction components, organic fatty acid silver salts are used as a silver ion donor, and compounds of the general formula (I) are used as a halogen ion donor as a photosensitive component of a heat-developable photosensitive material.
, (II) is particularly preferable in terms of photographic properties.

The reaction between the silver ion donor (a) and the halogen ion donor (b) of the present invention is carried out by a conventional reaction method, such as a forward flow method, a reverse flow method, or a simultaneous mixing method. For example, if (a) and (b) are both soluble in the reaction solvent, the simultaneous mixing method is selected depending on the type of a) and (b). If available, the backflow method is preferred.

The iridium ion donor (d) used in the present invention is an iridium salt or an iridium complex salt, such as a trihalogenated iridium salt, a tetrahalogenated iridium salt, a hexahalogenoiridium (III) salt, a hexahalogenoiridium (IV ), and useful specific compounds are iridium(III) chloride, iridium(IV) chloride
), sodium iridium (III) chloride dihydrate,
Sodium chloride iridium (IV) hexahydrate, etc.

In the present invention, the iridium ion donor (d) can be added as a separate liquid from the suppliers (a) and (b), or can be added as a mixture with (b). The method of adding each component during the reaction may be selected from a method of adding all at once, a method of adding intermittently, a method of adding continuously, or a method of combining these methods depending on the purpose. As a solvent for the iridium ion donor (d),
Polar organic solvents are preferred, and organic solvents having good compatibility with the organic solvent (c), such as polar alcohols or ketones, are particularly preferred. In addition, iridium ion donor (d
) Water may be added to the organic solvent to make it easier to dissolve.

In the present invention, a solvent-soluble polymer may be added to the reaction solution. The addition of a polymer soluble in an organic solvent allows uniform reaction of the halogen compounds of component (a) and component (b), and also prevents irregular growth and aggregation of the photosensitive silver halide formed. You can also do it. Polymers that can be used for this purpose are, for example, polyvinyl acetate, polyvinyl propionate, polymethyl methacrylate, ethyl cellulose, cellulose acetate, nitrocellulose, polyethylene, ethylene-vinyl acetate copolymers, chlorinated polyethylene, polyvinyl chloride, Vinyl chloride-vinyl acetate copolymer, chlorinated polypropylene, polyvinyl acetal, acrylic resin, polystyrene, epoxy resin, modified melamine resin,
Alkyd resin, polyamide, chlorinated rubber, acrylonitrile-butadiene-styrene terpolymer, silicone block copolymer, polyvinylpyrrolidone, polyethylene oxide, high molecular weight paraffin, and JP-A-47-9
Examples include vinyl copolymers described in Japanese Patent No. 432. Among the above polymers, preferred are:
Polyvinyl acetals are particularly preferred as polymers that can be dissolved in alcohols or ketones alone or in a mixed solvent with other organic solvents. The amount of the organic solvent-soluble polymer used is about 0.05 g to about 20 g per 1 g of silver salt of the silver ion donor of component (a).
Preferably it ranges from about 0.1 g to about 10 g.

Next, particularly preferred embodiments of the manufacturing method of the present invention will be explained. An organic fatty acid silver salt (e.g., silver stearate) is uniformly dispersed in a polar organic solvent (e.g., methyl alcohol) under a red safety light, and a polymer soluble in the organic solvent (e.g., polyvinyl butyral) is further added and dissolved. A dispersion containing a polymer and a silver ion donor is prepared. This dispersion is kept at a constant temperature, and a solution of a halogen ion donor in an organic solvent (for example, N
-bromsuccinimide-acetone) at the same rate, after at least 90% of the reaction steps of the silver ion donor (a) and the halogen ion donor (b) have completed, particularly preferably after 95% of the reaction step. An iridium ion solution (for example, sodium chloride iridium (IV) hexahydrate-methanol) is added separately and completed at the same time as the addition of the halogen ion donor is completed. The reaction time during this period is
from about 30 seconds to about 5 hours, preferably from about 3 minutes to 3 hours,
You can choose based on your purpose and operational needs. In the photosensitive silver halide thus obtained, most of the iridium ions contained therein are concentrated near the surface of the silver halide crystal. It should be noted that the above preparation has been explained by showing a preferred example, and is not limited thereto as long as a photosensitive silver halide meeting the purpose of the present invention can be prepared.

Furthermore, in the method for producing photosensitive silver halide of the present invention, the metal compounds disclosed in Japanese Patent Publications No. 2-6045 and No. 2-7447 can be involved in the reaction to control grains. Furthermore, the particle size and particle distribution can be controlled by measuring and controlling the silver ion concentration during the reaction.

In addition, in the method for producing photosensitive silver halide of the present invention, after the reaction is completed, the reaction solution is mixed in a solvent capable of precipitating the polymer used during the reaction, as disclosed in Japanese Patent Publication No. 2-7446. By doing so, reaction by-products or unreacted substances can be washed away.

Furthermore, in the method for producing photosensitive silver halide of the present invention, known chemical sensitization methods such as sulfur sensitization, gold sensitization, reduction sensitization, etc. can be applied to increase the inherent sensitivity. Spectral sensitization is also possible using known merocyanine dyes, hemicyanine dyes, cyanine dyes, and the like.

[0038]

[Examples] The present invention will be explained below according to Examples.
The present invention is not limited to these.

Example 1 (Production of photosensitive silver halide) Under red safety light, 3.6 g of lithium bromide and 7.2 g of polyvinyl butyral were dissolved in 120 ml of ethyl alcohol, kept at 30° C., and stirred. Below, 120ml of acetone in which 9g of silver trifluoroacetate prepared in advance was dissolved.
115 ml of 1 was added continuously over 6 minutes. Furthermore, add the remaining 5 ml to 6.7 m of iridium chloride (IV).
was added simultaneously with 5 ml of an ethanol solution of 50 g continuously over a period of 40 seconds. Water that is being stirred for a long time 1.2
A precipitate was obtained. After filtering and drying this, silver bromide-polyvinyl butyral solid containing iridium (
A-1) was obtained. For comparison, iridium chloride (IV
) was obtained without adding silver bromide-polyvinyl butyral solid (B-1).

(Production of heat-developable photosensitive material) Silver behenate 5
1g, behenic acid 39g, xylene 440ml and n
The mixture was placed in a dispersion solvent consisting of 440 ml of -butanol and dispersed using a homomixer. 80 g of polyvinyl butyral was added as a binder to this dispersion and stirred to prepare a polymer dispersion of silver salt. This dispersion liquid was divided into 90g portions, and the following silver bromide dispersions were mixed and dissolved in each portion. (1) 1.0 g (2
) The following components were sequentially added to 1.0 g of the prepared comparative solid material (B-1) to each of the above two types of silver bromide-containing silver behenate polymer dispersion to prepare a photosensitive slurry. did. 2,2'-bis-(2-hydroxy-3,5-
A solution consisting of 4 g of (dimethylphenyl)-3,5,5-trimethylhexane and 10 ml of ethanol 0.005 g of mercuric acetate A photosensitive slurry of these two types was spread onto a 50μ PET film for 1 m2.
It was applied so that the amount of silver per coat was 0.55 g and dried. Furthermore, on this coated surface, apply the following topcoat composition in an amount of 1 m2 when dry.
Coat and dry to give a weight of 2.0 g per sample (A-
2) , (B-2) was created. Topcoat composition cellulose acetate
15.0g phthalazinone
8.0g acetone
300
ml of the above samples (A-2) and (B-2) were exposed by xenon flash under red safe light through a step tablet with a density difference of 0.1,
Heat development was performed at ℃ for 5 seconds. The irradiation conditions were an exposure time of 10-5 seconds and an amount of light energy on the material surface of 0.2 mJ/cm2. For comparison, it was similarly exposed to tungsten light and thermally developed. However, the irradiation conditions were an exposure time of 1 sec and an amount of light energy on the material surface of 0.7 mJ/cm2. Each characteristic curve is shown in FIGS. 1 and 2. However, there is no correlation between the horizontal axis energies in FIGS. 1 and 2. As is clear from the results, it can be seen that the product of the present invention improves high illuminance failure.

Example 2 (Production of photosensitive silver halide) Under red safety light, 55.0 g of silver stearate was dispersed in 1 liter of isopropyl alcohol. Furthermore, 37.5 g of polyvinyl butyral resin was added and dissolved to prepare a polymer suspension dispersion of silver salt. Divide this into 10 equal parts and 50℃
N dissolved in 30 ml of acetone was added to each
- adding 2.6 g of bromsuccinimide in 30 minutes;
During that time, 5 ml of sodium chloride iridium (IV) hexahydrate-methanol was added at different times and concentrations (the amount and time of addition are listed in Table 1). Further, the reaction was continued for 30 minutes, and each mixture was poured into 400 ml of stirring water to obtain a precipitate. After filtering and drying, photosensitive silver halide (C-1), (D-1), (E-1), (F-1)
, (G-1), (H-1), (I-1), (J-1),
(K-1) and (L-1) were obtained. “Ir(IV
) Addition timing'', ``at the start'' means that the addition started at the same time as the addition of N-bromsuccinimide started, and the addition was made within 2 minutes, and ``intermediate time'' means 15 minutes after the start of the addition of N-bromsuccinimide. Indicates that it was added in 2 minutes, and indicates that it was added in 2 minutes.
"At the end of the addition" means that the addition was started 2 minutes before the end of the addition of N-bromsuccinimide and ended at the same time as the end of the addition of N-bromsuccinimide.

(Production of heat-developable photosensitive material) Produced in the same manner as in Example 1, but in this case photosensitive silver halide (
Using 0.95 g of each of C-1) to (L-1),
Image samples (C-2) to (L-2) corresponding to this were created. Exposure and development were performed in the same manner as in Example 1. Table 1 shows the results. The evaluation was performed on the following five scales. ◎: Improved, ○: Considerably improved, △: Slightly improved, -: No change, ×: Increased fog

[0043]

[Table 1]

Example 3 (Production of photosensitive silver halide) Under red safety light, 52.5 g of silver behenate was dispersed in 840 ml of ethyl alcohol. Furthermore, 31.5 g of polyvinyl butyral resin was added and dissolved to prepare a polymer suspension dispersion of silver salt. Divide this into 7 equal parts, adjust the temperature to 60°C, and add 2 N-bromsuccinimide to each part while stirring.
．． A mixed solvent of acetone/methanol (5/1; volume ratio) in which 4 g and 0.009 g of sodium bromide were dissolved 25
ml was uniformly dropped over 60 minutes. At this time, sodium iridium (IV) chloride hexahydrate-methanol 5m
1 was added to the silver halide at the same concentration per unit volume by varying the timing and amount of addition. Furthermore, 6
Continue the reaction for 0 minutes, stirring each 500 ml of water.
to obtain a precipitate. After filtering and drying, photosensitive silver halide (M-1), (N-1), (O-1), (P
-1), (Q-1), (R-1), (S-1) were obtained. Table 2 shows the timing of addition of each sample.

(Production of heat-developable photosensitive material) Produced in the same manner as in Example 1 except that 1.0 g of each of photosensitive silver halides (M-1) to (S-1) was used, and the corresponding Image samples (M-2) to (S-2) were prepared. Exposure and development were performed in the same manner as in Example 1. Table 2 shows the results. In Table 2, * indicates something that cannot be measured due to high illuminance failure. Sample N-2 using photosensitive silver halide of the present invention
~Q-2 had low fog density and improved high illuminance failure. Moreover, it can be seen that samples P-2 and Q-2 are particularly excellent.

[0046]

[Table 2]

Application Example 1 A heat-developable photosensitive material (P) was prepared in the same manner as the imaging sample (P-2) produced in Example 3, but in this case, the following sensitizing dye was used under green safe light. 2 mg of N,N-dimethylformamide was dissolved in 1 ml of N,N-dimethylformamide, and spectrally sensitized by adding the solution. Characters were written on this at 5 x 10-6 seconds per dot using a He-Ne laser device (5 mW) and heat developed to obtain a clear image.

[0048]

[Chemical formula 3]

[0049]

[Effects of the Invention] According to the present invention, a method for producing photosensitive silver halide is suitable for dry heat-developable photosensitive materials that are compatible with high-speed image writing using light sources such as gas lasers and semiconductor lasers, have excellent image quality, and are maintenance-free. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a graph showing characteristic curves when a sample of the present invention and a comparative sample were exposed to xenon flash and thermally developed.

FIG. 2 is a graph showing characteristic curves when a sample of the present invention and a comparative sample were exposed to tungsten light and thermally developed.

Claims (4)

[Claims] Claim 1: In the step of producing photosensitive silver halide by reacting a silver ion donor (a) and a halogen ion donor (b) in an organic solvent (c), an iridium ion donor (d) is reacted with the iridium ion donor (d). 1. A method for producing photosensitive silver halide, which comprises adding the following: 2. The iridium ion donor (d) is a silver ion donor (a) and a halogen ion donor (b).
2. The method for producing photosensitive silver halide according to claim 1, wherein the method is added after at least 90% of the reaction steps have been completed. 3. The iridium ion donor (d) is 5× relative to the total silver ion donor (a) involved in the reaction.
3. The method for producing photosensitive silver halide according to claim 2, wherein the photosensitive silver halide is added in a molar ratio of 10<-5> to 5*10<-3>. 4. The silver ion donor (a) is an organic fatty acid silver salt having 5 or more carbon atoms, and the halogen ion donor (a) is an organic fatty acid silver salt having 5 or more carbon atoms.
4. The method for producing photosensitive silver halide according to claim 3, wherein b) is a combination of N-halogeno compounds.